Sensor misalignment compensation

CROSS-REFERENCE TO RELATED APPLICATIONS

0001This application is a continuation of U.S. patent application Ser. No. 17/180,249 filed on Feb. 19, 2021, which is a continuation of U.S. patent application Ser. No. 16/706,162 filed on Dec. 6, 2019, both of which are incorporated herein by reference in their entirety.

TECHNICAL FIELD

0002The present subject matter relates to wearable devices, e.g., eyewear devices, having stereoscopic camera systems and techniques for compensating for differences in pitch between sensors/cameras of the stereoscopic camera systems.

BACKGROUND

0003Stereoscopic camera systems utilize a pair of sensors/cameras to capture images of a scene from two viewpoints. A conventional camera in such systems typically utilizes either a charge coupled device (CCD) sensor or a complementary metal oxide semiconductor (CMOS) sensor to capture an image frame of a scene. CCD sensors typically use a global shutter, which simultaneously captures the entire frame. CMOS sensors, on the other hand, typically use a rolling shutter, which sequentially exposes different parts of the frame at different points in time.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawing figures depict one or more implementations, by way of example only, not by way of limitations. In the figures, like reference numerals refer to the same or similar elements with a letter designation added to differentiate between the same or similar elements. The letter designation may be dropped when the same or similar elements are referred to collectively or when referring to a non-specific one of the same or similar elements.

<figref idref="DRAWINGS">FIG. <b>1</b>A</figref> is a side view of an example hardware configuration of an eyewear device utilized in a camera misalignment compensation system.

<figref idref="DRAWINGS">FIG. <b>1</b>B</figref> is a top cross-sectional view of a right electronic housing of the eyewear device of <figref idref="DRAWINGS">FIG. <b>1</b>A</figref> depicting a right visible light camera of a depth-capturing camera, and a circuit board.

<figref idref="DRAWINGS">FIG. <b>1</b>C</figref> is a left side view of an example hardware configuration of an eyewear device of <figref idref="DRAWINGS">FIG. <b>1</b>A</figref>, which shows a left visible light camera of the depth-capturing camera.

<figref idref="DRAWINGS">FIG. <b>1</b>D</figref> is a top cross-sectional view of a left electronic housing of the eyewear device of <figref idref="DRAWINGS">FIG. <b>1</b>C</figref> depicting the left visible light camera of the depth-capturing camera, and the circuit board.

<figref idref="DRAWINGS">FIG. <b>2</b>A</figref> is a side view of another example hardware configuration of an eyewear device utilized in the camera misalignment compensation system, which shows the right visible light camera and a depth sensor of the depth-capturing camera to generate an initial depth image of a sequence of initial depth images (e.g., in an initial video).

<figref idref="DRAWINGS">FIGS. <b>2</b>B and <b>2</b>C</figref> are rear views of example hardware configurations of the eyewear device, including two different types of image displays.

<figref idref="DRAWINGS">FIG. <b>3</b></figref> shows a rear perspective sectional view of the eyewear device of <figref idref="DRAWINGS">FIG. <b>2</b>A</figref> depicting an infrared camera of the depth sensor, a frame front, a frame back, and a circuit board.

<figref idref="DRAWINGS">FIG. <b>4</b></figref> is a cross-sectional view taken through the infrared camera and the frame of the eyewear device of <figref idref="DRAWINGS">FIG. <b>3</b></figref>.

<figref idref="DRAWINGS">FIG. <b>5</b></figref> shows a rear perspective view of the eyewear device of <figref idref="DRAWINGS">FIG. <b>2</b>A</figref> depicting an infrared emitter of the depth sensor, the infrared camera of the depth sensor, the frame front, the frame back, and the circuit board.

<figref idref="DRAWINGS">FIG. <b>6</b></figref> is a cross-sectional view taken through the infrared emitter and the frame of the eyewear device of <figref idref="DRAWINGS">FIG. <b>5</b></figref>.

<figref idref="DRAWINGS">FIG. <b>7</b></figref> depicts an example of a pattern of infrared light emitted by the infrared emitter of the depth sensor and reflection variations of the emitted pattern of infrared light captured by the infrared camera of the depth sensor of the eyewear device to measure depth of pixels in a raw image to generate the initial depth images from the initial video.

<figref idref="DRAWINGS">FIG. <b>8</b>A</figref> depicts an example of infrared light captured by an infrared camera of a depth sensor as an infrared image and visible light captured by a visible light camera as a raw image to generate an initial depth image of a scene.

<figref idref="DRAWINGS">FIG. <b>8</b>B</figref> depicts an example of visible light captured by the left visible light camera as left raw image and visible light captured by the right visible light camera as a right raw image to generate the initial depth image of a three-dimensional scene.

<figref idref="DRAWINGS">FIG. <b>8</b>C</figref> depicts initial images captured using visible light cameras.

<figref idref="DRAWINGS">FIG. <b>8</b>D</figref> depicts the images of <figref idref="DRAWINGS">FIG. <b>8</b>C</figref> after rectification and compensation to obtain calibrated images.

<figref idref="DRAWINGS">FIG. <b>8</b>E</figref> depicts a graph showing readout times for image rows for a camera having a rolling shutter in accordance with the prior art.

<figref idref="DRAWINGS">FIG. <b>8</b>F</figref> depicts images captured by a stereoscopic camera system in a static system where the cameras of the camera system have different pitch angles.

<figref idref="DRAWINGS">FIG. <b>8</b>G</figref> depicts images captured by a stereo camera system in a dynamic system where the cameras of the camera system have different pitch angles and the camera is moving vertically.

<figref idref="DRAWINGS">FIG. <b>9</b></figref> is a high-level functional block diagram of an example camera misalignment compensation system including the eyewear device with a depth-capturing camera to generate initial depth images, a mobile device, and a server system connected via various networks.

<figref idref="DRAWINGS">FIG. <b>10</b></figref> shows an example of a hardware configuration for the mobile device of the camera misalignment compensation system of <figref idref="DRAWINGS">FIG. <b>9</b></figref>.

<figref idref="DRAWINGS">FIGS. <b>11</b>A, <b>11</b>B, and <b>11</b>C</figref> are flowcharts of methods the camera misalignment compensation system implements to compensate for misalignment of cameras in a stereoscopic camera system.

DETAILED DESCRIPTION

0026In typical stereoscopic camera systems, the sensors/cameras are synchronized and operate in a master-slave model. The cameras are driven by the same clock and use the same exposure settings. The cameras of a device may be misaligned (e.g., on the Y-axis; vertical axis) due to mechanical misalignment tolerances during assembly at the factory. Misalignment of the cameras cause feature points from a scene to be projected to different sensor lines. While stereo calibration can often compensate for these differences in static scenes, they may not be able to do so for moving objects and/or when the observer is moving.

0027Assuming a feature is projected to line Y<b>1</b> on a first sensor (sensor<b>1</b>) and to line Y<b>2</b> on a second sensor (sensor<b>2</b>), lines Y<b>1</b> and Y<b>2</b> are exposed at different times when using a rolling shutter read out method (which is typical for CMOS sensors). Assuming it takes time, t, to read out a single sensor line, the time difference, T, equals t*abs(Y<b>1</b>−Y<b>2</b>). If the object or the cameras are moving, this time difference will result in different positions of the feature point on two sensors/cameras, which complicates stereo matching of the feature point. The impact of this misalignment may be addressed after exposure/capture of the images or before exposure/capture of the images. In one approach the vertical blanking interval (V-blank period) is maximized to reduce time ‘t’ and minimize ‘T’. In another approach, exposure delay counted in sensor lines (i.e., in ‘t’ units) is introduced in order to postpone readout from one of the sensors such that lines Y<b>1</b> and Y<b>2</b> are exposed at substantially the same time. Exposure delay is a feature available in modern sensors from, for example, Sony Corporation of Minato, Japan. During stereo calibration at the factory, the misalignment information may be stored on the device. On bootup, the calibration data is read out and the misalignment angle is converted into the required delay in lines. Prior to camera activation the sensors are configured with the delay times. The autoexposure algorithm may be adjusted to account for the worst-case delay.

0028In this detailed description, numerous specific details are set forth by way of examples in order to provide a thorough understanding of the relevant teachings. However, it should be apparent to those skilled in the art that the present teachings may be practiced without such details. In other instances, description of well-known methods, procedures, components, and circuitry are set forth at a relatively high-level, without detail, in order to avoid unnecessarily obscuring aspects of the present teachings.

0029As used herein, the term “coupled” or “connected” refers to any logical, optical, physical or electrical connection, link or the like by which electrical or magnetic signals produced or supplied by one system element are imparted to another coupled or connected element. Unless described otherwise, coupled or connected elements or devices are not necessarily directly connected to one another and may be separated by intermediate components, elements or communication media that may modify, manipulate or carry the electrical signals. The term “on” means directly supported by an element or indirectly supported by the element through another element integrated into or supported by the element.

0030The orientations of the eyewear device, associated components and any complete devices incorporating a depth-capturing camera such as shown in any of the drawings, are given by way of example only, for illustration and discussion purposes. In operation for camera misalignment compensation, the eyewear device may be oriented in any other direction suitable to the application of the eyewear device, for example up, down, sideways, or any other orientation. Also, to the extent used herein, any directional term, such as front, rear, inwards, outwards, towards, left, right, lateral, longitudinal, up, down, upper, lower, top, bottom, side, horizontal, vertical, and diagonal are used by way of example only, and are not limiting as to direction or orientation of any depth-capturing camera or component of the depth-capturing camera constructed as otherwise described herein.

0031Additional objects, advantages and novel features of the examples will be set forth in part in the following description, and in part will become apparent to those skilled in the art upon examination of the following and the accompanying drawings or may be learned by production or operation of the examples. The objects and advantages of the present subject matter may be realized and attained by means of the methodologies, instrumentalities and combinations particularly pointed out in the appended claims.

0032Reference now is made in detail to the examples illustrated in the accompanying drawings and discussed below.

0033As shown in <figref idref="DRAWINGS">FIGS. <b>1</b>A and <b>1</b>B</figref>, the eyewear device <b>100</b> includes a right visible light camera <b>114</b>B. The eyewear device <b>100</b> can include multiple visible light cameras <b>114</b>A and <b>114</b>B that form a passive type of depth-capturing camera, such as stereo camera, of which the right visible light camera <b>114</b>B is located on a right electronic housing <b>110</b>B. As shown in <figref idref="DRAWINGS">FIGS. <b>1</b>C and <b>1</b>D</figref>, the eyewear device <b>100</b> also includes a left visible light camera <b>114</b>A.

0034Left and right visible light cameras <b>114</b>A and <b>114</b>B are sensitive to the visible light range wavelength. Each of the visible light cameras <b>114</b>A and <b>114</b>B have a different frontward facing field of view which are overlapping to allow three-dimensional depth images to be generated, for example, right visible light camera <b>114</b>B has the depicted right field of view <b>111</b>B (see <figref idref="DRAWINGS">FIGS. <b>8</b>A and <b>8</b>B</figref>). Generally, a “field of view” is the part of the scene that is visible through the camera at a position and orientation in space. Objects or object features outside the field of view <b>111</b>A and <b>111</b>B when the image is captured by the visible light camera are not recorded in a raw image (e.g., photograph or picture). The field of view describes an angle range or extent which the image sensor of the visible light camera <b>114</b>A and <b>114</b>B picks up electromagnetic radiation of a given scene in a captured image of the given scene. Field of view can be expressed as the angular size of the view cone, i.e., an angle of view. The angle of view can be measured horizontally, vertically, or diagonally.

0035In an example, visible light cameras <b>114</b>A and <b>114</b>B have a field of view with an angle of view between 15° to 30°, for example 24°, and have a resolution of 480×480 pixels or greater. The “angle of coverage” describes the angle range that a lens of visible light cameras <b>114</b>A and <b>114</b>B or infrared camera <b>220</b> (see <figref idref="DRAWINGS">FIG. <b>2</b>A</figref>) can effectively image. Typically, the image circle produced by a camera lens is large enough to cover the film or sensor completely, possibly including some vignetting (i.e., a reduction of an image's brightness or saturation at the periphery compared to the image center). If the angle of coverage of the camera lens does not fill the sensor, the image circle will be visible, typically with strong vignetting toward the edge, and the effective angle of view will be limited to the angle of coverage.

0036Examples of such visible lights camera <b>114</b>A and <b>114</b>B include a high-resolution complementary metal-oxide-semiconductor (CMOS) image sensor and a video graphic array (VGA) camera, such as 640 p (e.g., 640×480 pixels for a total of 0.3 megapixels), 720 p, or 1080 p. As used herein, the term “overlapping” when referring to field of view means the matrix of pixels in the generated raw image(s) or infrared image of a scene overlap by 30% or more. As used herein, the term “substantially overlapping” when referring to field of view means the matrix of pixels in the generated raw image(s) or infrared image of a scene overlap by 50% or more. Suitable visible light cameras <b>114</b> include complementary metal-oxide-semiconductor (CMOS) sensor cameras with rolling shutter readout. In one example, the cameras <b>114</b> include a V-blank period setting for use in minimizing the time difference, T, between feature points obtained by two separate cameras. In another example, the cameras <b>114</b> include an exposure delay setting that is counted in sensor lines, such as cameras available from Sony Corporation of Minato, Japan, to postpose readout of one of the cameras in order to expose feature points falling on different lines at substantially the same time. Other suitable cameras will be understood by one of skill in the art from the description herein.

0037Image sensor data from the visible light cameras <b>114</b>A and <b>114</b>B are captured along with geolocation data, digitized by an image processor, and stored in a memory. The captured left and right raw images captured by respective visible light cameras <b>114</b>A and <b>114</b>B are in the two-dimensional space domain and comprise a matrix of pixels on a two-dimensional coordinate system that includes an X axis for horizontal position and a Y axis for vertical position. Each pixel includes a color attribute (e.g., a red pixel light value, a green pixel light value, and/or a blue pixel light value); and a position attribute (e.g., an X location coordinate and a Y location coordinate).

0038To provide stereoscopic vision, visible light cameras <b>114</b>A and <b>114</b>B may be coupled to an image processor (element <b>912</b> of <figref idref="DRAWINGS">FIG. <b>9</b></figref>) for digital processing along with a timestamp in which the image of the scene is captured. Image processor <b>912</b> includes circuitry to receive signals from the visible light cameras <b>114</b>A and <b>114</b>B and process those signals from the visible light camera <b>114</b> into a format suitable for storage in the memory. The timestamp can be added by the image processor or other processor, which controls operation of the visible light cameras <b>114</b>A and <b>114</b>B. Visible light cameras <b>114</b>A and <b>114</b>B allow the depth-capturing camera to simulate human binocular vision. The depth-capturing camera provides the ability to reproduce three-dimensional images based on two captured images from the visible light cameras <b>114</b>A and <b>114</b>B having the same timestamp. Such three-dimensional images allow for an immersive life-like experience, e.g., for virtual reality or video gaming. Three-dimensional depth videos may be produced by stitching together a sequence of three-dimensional depth images with associated time coordinates for a presentation time in a depth video.

0039For stereoscopic vision, a pair of raw red, green, and blue (RGB) images are captured of a scene at a moment in time—one image for each of the left and right visible light cameras <b>114</b>A and <b>114</b>B. When the pair of captured raw images from the frontward facing left and right field of views <b>111</b>A and <b>111</b>B of the left and right visible light cameras <b>114</b>A and <b>114</b>B are processed (e.g., by the image processor), depth images are generated, and the generated depth images can be perceived by a user on the optical assembly <b>180</b>A and <b>180</b>B or other image display(s) (e.g., of a mobile device). The generated depth images are in the three-dimensional space domain and can comprise a matrix of vertices on a three-dimensional location coordinate system that includes an X axis for horizontal position (e.g., length), a Y axis for vertical position (e.g., height), and a Z axis for a depth position (e.g., distance).

0040A depth video further associates each of a sequence of generated depth images with a time coordinate on a time (T) axis for a presentation time in a depth video (e.g., each depth image includes spatial components as well as a temporal component). The depth video can further include one or more input parameter components (e.g., an audio component such as an audio track or stream, a biometric comp such as a heartrate graph, etc.), which may be captured by an input device such as a microphone or a heartrate monitor. Each vertex includes a color attribute (e.g., a red pixel light value, a green pixel light value, and/or a blue pixel light value); a position attribute (e.g., an X location coordinate, a Y location coordinate, and a Z location coordinate); a texture attribute, and/or a reflectance attribute. The texture attribute quantifies the perceived texture of the depth image, such as the spatial arrangement of color or intensities in a region of vertices of the depth image.

0041Generally, perception of depth arises from the disparity of a given 3D point in the left and right raw images captured by visible light cameras <b>114</b>A and <b>114</b>B. Disparity is the difference in image location of the same 3D point when projected under perspective of the visible light cameras <b>114</b>A and <b>114</b>B (d=x_leftx_right). For visible light cameras <b>114</b>A and <b>114</b>B with parallel optical axes, focal length f, baseline b, and corresponding image points (x_left, y_left) and (x_right, y_right), the location of a 3D point (Z axis location coordinate) can be derived utilizing triangulation which determines depth from disparity. Typically, depth of the 3D point is inversely proportional to disparity. A variety of other techniques can also be used for the generation of three-dimensional depth images.

0042In an example, a camera misalignment compensation system includes the eyewear device <b>100</b>. The eyewear device <b>100</b> includes a frame <b>105</b> and a left temple <b>110</b>A extending from a left lateral side <b>170</b>A of the frame <b>105</b> and a right temple <b>110</b>B extending from a right lateral side <b>170</b>B of the frame <b>105</b>. Eyewear device <b>100</b> further includes a depth-capturing camera. The depth-capturing camera includes: (i) at least two visible light cameras with overlapping fields of view; or (ii) a least one visible light camera <b>114</b>A and <b>114</b>B and a depth sensor (element <b>213</b> of <figref idref="DRAWINGS">FIG. <b>2</b>A</figref>). In one example, the depth-capturing camera includes a left visible light camera <b>114</b>A with a left field of view <b>111</b>A connected to the frame <b>105</b> or the left temple <b>110</b>A to capture a left image of the scene. Eyewear device <b>100</b> further includes a right visible light camera <b>114</b>B connected to the frame <b>105</b> or the right temple <b>110</b>B with a right field of view <b>111</b>B to capture (e.g., simultaneously with the left visible light camera <b>114</b>A) a right image of the scene which partially overlaps the left image.

0043The camera misalignment compensation system further includes a computing device, such as a host computer (e.g., mobile device <b>990</b> of <figref idref="DRAWINGS">FIGS. <b>9</b> and <b>10</b></figref>) coupled to eyewear device <b>100</b> over a network. The camera misalignment compensation system further includes an image display (optical assembly <b>180</b>A and <b>180</b>B of eyewear device; image display <b>1080</b> of mobile device <b>990</b> of <figref idref="DRAWINGS">FIG. <b>10</b></figref>) for presenting (e.g., displaying) a video including images. The camera misalignment compensation system further includes an image display driver (element <b>942</b> of eyewear device <b>100</b> of <figref idref="DRAWINGS">FIG. <b>9</b></figref>; element <b>1090</b> of mobile device <b>990</b> of <figref idref="DRAWINGS">FIG. <b>10</b></figref>) coupled to the image display (optical assembly <b>180</b>A and <b>180</b>B of eyewear device; image display <b>1080</b> of mobile device <b>990</b> of <figref idref="DRAWINGS">FIG. <b>10</b></figref>) to control the image display to present the initial video.

0044In some examples, user input is received to indicate that the user desires to capture an image. For example, the camera misalignment compensation system further includes a user input device to receive a user input. Examples of user input devices include a touch sensor (element <b>991</b> of <figref idref="DRAWINGS">FIG. <b>9</b></figref> for the eyewear device <b>100</b>), a touch screen display (element <b>1091</b> of <figref idref="DRAWINGS">FIG. <b>10</b></figref> for the mobile device <b>1090</b>), and a computer mouse for a personal computer or a laptop computer. The camera misalignment compensation system further includes a processor (element <b>932</b> of eyewear device <b>100</b> of <figref idref="DRAWINGS">FIG. <b>9</b></figref>; element <b>1030</b> of mobile device <b>990</b> of <figref idref="DRAWINGS">FIG. <b>10</b></figref>) coupled to the eyewear device <b>100</b> and the depth-capturing camera. The camera misalignment compensation system further includes a memory (element <b>934</b> of eyewear device <b>100</b> of <figref idref="DRAWINGS">FIG. <b>9</b></figref>; elements <b>1040</b>A-B of mobile device <b>990</b> of <figref idref="DRAWINGS">FIG. <b>10</b></figref>) accessible to the processor, and programming in the memory (element <b>945</b> of eyewear device <b>100</b> of <figref idref="DRAWINGS">FIG. <b>9</b></figref>; element <b>945</b> of mobile device <b>990</b> of <figref idref="DRAWINGS">FIG. <b>10</b></figref>), for example in the eyewear device <b>100</b> itself, mobile device (element <b>990</b> of <figref idref="DRAWINGS">FIG. <b>9</b></figref>), or another part of the camera misalignment compensation system (e.g., server system <b>998</b> of <figref idref="DRAWINGS">FIG. <b>9</b></figref>).

0045Execution of the camera misalignment programming (element <b>945</b> of <figref idref="DRAWINGS">FIG. <b>9</b></figref>) by the processor (element <b>932</b> of <figref idref="DRAWINGS">FIG. <b>9</b></figref>) configures the eyewear device <b>100</b> to compensate for camera misalignment when processing raw images <b>858</b>A-B after rectification. Each of the initial depth images is associated with a time coordinate on a time (T) axis for a presentation time, for example, based on initial images <b>957</b>A-B in the initial video. The initial depth image is formed of a matrix of vertices. Each vertex represents a pixel in a three-dimensional scene. Each vertex has a position attribute. The position attribute of each vertex is based on a three-dimensional location coordinate system and includes an X location coordinate on an X axis for horizontal position, a Y location coordinate on a Y axis for vertical position, and a Z location coordinate on a Z axis for a depth position.

0046Execution of the camera misalignment compensation programming (element <b>945</b> of <figref idref="DRAWINGS">FIG. <b>10</b></figref>) by the processor (element <b>945</b> of <figref idref="DRAWINGS">FIG. <b>10</b></figref>) configures the mobile device (element <b>990</b> of <figref idref="DRAWINGS">FIG. <b>10</b></figref>) of the camera misalignment compensation system to perform the following functions. Mobile device (element <b>990</b> of <figref idref="DRAWINGS">FIG. <b>10</b></figref>) identifies a pitch angle offset between the left and right visible light camera <b>114</b> (or between a visible light camera and an infrared depth camera). Mobile device (element <b>990</b> of <figref idref="DRAWINGS">FIG. <b>10</b></figref>) then determines misalignment of the first and second cameras from the identified pitch angle offset. Next, mobile device (element <b>990</b> of <figref idref="DRAWINGS">FIG. <b>10</b></figref>) produces a stereoscopic image on the display from the first and second image streams with the introduced relative compensation delay to compensate for the pitch angle offset.

0047<figref idref="DRAWINGS">FIG. <b>1</b>B</figref> is a top cross-sectional view of a right electronic housing <b>110</b>B of the eyewear device <b>100</b> of <figref idref="DRAWINGS">FIG. <b>1</b>A</figref> depicting the right visible light camera <b>114</b>B of the depth-capturing camera, and a circuit board. <figref idref="DRAWINGS">FIG. <b>1</b>C</figref> is a left side view of an example hardware configuration of an eyewear device <b>100</b> of <figref idref="DRAWINGS">FIG. <b>1</b>A</figref>, which shows a left visible light camera <b>114</b>A of the depth-capturing camera. <figref idref="DRAWINGS">FIG. <b>1</b>D</figref> is a top cross-sectional view of a left electronic housing <b>110</b>A of the eyewear device of <figref idref="DRAWINGS">FIG. <b>1</b>C</figref> depicting the left visible light camera <b>114</b>A of the depth-capturing camera, and a circuit board. Construction and placement of the left visible light camera <b>114</b>A is substantially similar to the right visible light camera <b>114</b>B, except the connections and coupling are on the left lateral side <b>170</b>A. As shown in the example of <figref idref="DRAWINGS">FIG. <b>1</b>B</figref>, the eyewear device <b>100</b> includes the right visible light camera <b>114</b>B and a circuit board, which may be a flexible printed circuit board (PCB) <b>140</b>B. The right hinge <b>126</b>B connects the right electronic housing <b>110</b>B to a right temple <b>125</b>B of the eyewear device <b>100</b>. In some examples, components of the right visible light camera <b>114</b>B, the flexible PCB <b>140</b>B, or other electrical connectors or contacts may be located on the right temple <b>125</b>B or the right hinge <b>126</b>B.

0048The right electronic housing <b>110</b>B includes electronic housing body <b>211</b> and an electronic housing cap, with the electronic housing cap omitted in the cross-section of <figref idref="DRAWINGS">FIG. <b>1</b>B</figref>. Disposed inside the right electronic housing <b>110</b>B are various interconnected circuit boards, such as PCBs or flexible PCBs, that include controller circuits for right visible light camera <b>114</b>B, microphone(s), low-power wireless circuitry (e.g., for wireless short-range network communication via Bluetooth™), high-speed wireless circuitry (e.g., for wireless local area network communication via Wi-Fi).

0049The right visible light camera <b>114</b>B is coupled to or disposed on the flexible PCB <b>240</b> and covered by a visible light camera cover lens, which is aimed through opening(s) formed in the frame <b>105</b>. For example, the right rim <b>107</b>B of the frame <b>105</b> is connected to the right electronic housing <b>110</b>B and includes the opening(s) for the visible light camera cover lens. The frame <b>105</b> includes a front-facing side configured to face outwards away from the eye of the user. The opening for the visible light camera cover lens is formed on and through the front-facing side. In the example, the right visible light camera <b>114</b>B has an outward facing field of view <b>111</b>B with a line of sight or perspective of the right eye of the user of the eyewear device <b>100</b>. The visible light camera cover lens can also be adhered to an outward facing surface of the right electronic housing <b>110</b>B in which an opening is formed with an outward facing angle of coverage, but in a different outward direction. The coupling can also be indirect via intervening components.

0050Left (first) visible light camera <b>114</b>A is connected to a left image display of left optical assembly <b>180</b>A and captures a left eye viewed scene observed by a wearer of the eyewear device <b>100</b> in a left raw image. Right (second) visible light camera <b>114</b>B is connected to a right image display of right optical assembly <b>180</b>B and captures a right eye viewed scene observed by the wearer of the eyewear device <b>100</b> in a right raw image. The left raw image and the right raw image partially overlap for use in presenting a three-dimensional observable space of a generated depth image.

0051Flexible PCB <b>140</b>B is disposed inside the right electronic housing <b>110</b>B and is coupled to one or more other components housed in the right electronic housing <b>110</b>B. Although shown as being formed on the circuit boards of the right electronic housing <b>110</b>B, the right visible light camera <b>114</b>B can be formed on the circuit boards of the left electronic housing <b>110</b>A, the temples <b>125</b>A and <b>125</b>B, or frame <b>105</b>.

0052<figref idref="DRAWINGS">FIG. <b>2</b>A</figref> is a side view of another example hardware configuration of an eyewear device <b>100</b> utilized in the camera misalignment compensation system. As shown, the depth-capturing camera includes a left visible light camera <b>114</b>A and a depth sensor <b>213</b> on a frame <b>105</b> to generate an initial depth image of a sequence of initial depth images (e.g., in an initial video). Instead of utilizing at least two visible light cameras <b>114</b>A and <b>114</b>B to generate the initial depth image, here a single visible light camera <b>114</b>A and the depth sensor <b>213</b> are utilized to generate depth images. The infrared camera <b>220</b> of the depth sensor <b>213</b> has an outward facing field of view that substantially overlaps with the left visible light camera <b>114</b>A for a line of sight of the eye of the user. As shown, the infrared emitter <b>215</b> and the infrared camera <b>220</b> are co-located on the upper portion of the left rim <b>107</b>A with the left visible light camera <b>114</b>A.

0053In the example of <figref idref="DRAWINGS">FIG. <b>2</b>A</figref>, the depth sensor <b>213</b> of the eyewear device <b>100</b> includes an infrared emitter <b>215</b> and an infrared camera <b>220</b> which captures an infrared image. Visible light cameras <b>114</b>A and <b>114</b>B typically include a blue light filter to block infrared light detection, in an example, the infrared camera <b>220</b> is a visible light camera, such as a low resolution video graphic array (VGA) camera (e.g., 640×480 pixels for a total of 0.3 megapixels), with the blue filter removed. The infrared emitter <b>215</b> and the infrared camera <b>220</b> are co-located on the frame <b>105</b>, for example, both are shown as connected to the upper portion of the left rim <b>107</b>A. As described in further detail below, the frame <b>105</b> or one or more of the left and right electronic housings <b>110</b>A and <b>110</b>B include a circuit board that includes the infrared emitter <b>215</b> and the infrared camera <b>220</b>. The infrared emitter <b>215</b> and the infrared camera <b>220</b> can be connected to the circuit board by soldering, for example.

0054Other arrangements of the infrared emitter <b>215</b> and infrared camera <b>220</b> can be implemented, including arrangements in which the infrared emitter <b>215</b> and infrared camera <b>220</b> are both on the right rim <b>107</b>A, or in different locations on the frame <b>105</b>, for example, the infrared emitter <b>215</b> is on the left rim <b>107</b>B and the infrared camera <b>220</b> is on the right rim <b>107</b>B. However, the at least one visible light camera <b>114</b>A and the depth sensor <b>213</b> typically have substantially overlapping fields of view to generate three-dimensional depth images. In another example, the infrared emitter <b>215</b> is on the frame <b>105</b> and the infrared camera <b>220</b> is on one of the electronic housings <b>110</b>A and <b>110</b>B, or vice versa. The infrared emitter <b>215</b> can be connected essentially anywhere on the frame <b>105</b>, left electronic housing <b>110</b>A, or right electronic housing <b>110</b>B to emit a pattern of infrared in the light of sight of the eye of the user. Similarly, the infrared camera <b>220</b> can be connected essentially anywhere on the frame <b>105</b>, left electronic housing <b>110</b>A, or right electronic housing <b>110</b>B to capture at least one reflection variation in the emitted pattern of infrared light of a three-dimensional scene in the light of sight of the eye of the user.

0055The infrared emitter <b>215</b> and infrared camera <b>220</b> are arranged to face outwards to pick up an infrared image of a scene with objects or object features that the user wearing the eyewear device <b>100</b> observes. For example, the infrared emitter <b>215</b> and infrared camera <b>220</b> are positioned directly in front of the eye, in the upper part of the frame <b>105</b> or in the electronic housings <b>110</b>A and <b>110</b>B at either ends of the frame <b>105</b> with a forward facing field of view to capture images of the scene which the user is gazing at, for measurement of depth of objects and object features.

0056In one example, the infrared emitter <b>215</b> of the depth sensor <b>213</b> emits infrared light illumination in the forward-facing field of view of the scene, which can be near-infrared light or other short-wavelength beam of low-energy radiation. Alternatively, or additionally, the depth sensor <b>213</b> may include an emitter that emits other wavelengths of light besides infrared and the depth sensor <b>213</b> further includes a camera sensitive to that wavelength that receives and captures images with that wavelength. As noted above, the eyewear device <b>100</b> is coupled to a processor and a memory, for example in the eyewear device <b>100</b> itself or another part of the camera misalignment compensation system. Eyewear device <b>100</b> or the camera misalignment compensation system can subsequently process the captured infrared image during generation of three-dimensional depth images of the depth videos, such as the initial depth images from the initial video.

0057<figref idref="DRAWINGS">FIGS. <b>2</b>B and <b>2</b>C</figref> are rear views of example hardware configurations of the eyewear device <b>100</b>, including two different types of image displays. Eyewear device <b>100</b> is in a form configured for wearing by a user, which are eyeglasses in the example. The eyewear device <b>100</b> can take other forms and may incorporate other types of frameworks, for example, a headgear, a headset, or a helmet.

0058In the eyeglasses example, eyewear device <b>100</b> includes a frame <b>105</b> including a left rim <b>107</b>A connected to a right rim <b>107</b>B via a bridge <b>106</b> adapted for a nose of the user. The left and right rims <b>107</b>A-B include respective apertures <b>175</b>A and <b>175</b>B which hold a respective optical element <b>180</b>A and <b>180</b>B, such as a lens and a display device. As used herein, the term lens is meant to cover transparent or translucent pieces of glass or plastic having curved and/or flat surfaces that cause light to converge/diverge or that cause little or no convergence or divergence.

0059Although shown as having two optical elements <b>180</b>A and <b>180</b>B, the eyewear device <b>100</b> can include other arrangements, such as a single optical element or may not include any optical element <b>180</b>A and <b>180</b>B depending on the application or intended user of the eyewear device <b>100</b>. As further shown, eyewear device <b>100</b> includes a left electronic housing <b>110</b>A (including a left camera <b>114</b>A) adjacent the left lateral side <b>170</b>A of the frame <b>105</b> and a right electronic housing <b>110</b>B (including a right camera <b>114</b>B) adjacent the right lateral side <b>170</b>B of the frame <b>105</b>. The electronic housings <b>110</b>A and <b>110</b>B may be integrated into the frame <b>105</b> on the respective sides <b>170</b>A and <b>170</b>B (as illustrated) or implemented as separate components attached to the frame <b>105</b> on the respective sides <b>170</b>A and <b>170</b>B. Alternatively, the electronic housings <b>110</b>A and <b>110</b>B may be integrated into temples (not shown) attached to the frame <b>105</b>.

0060In one example, the image display of the optical assembly <b>180</b>A and <b>180</b>B includes an integrated image display. As shown in <figref idref="DRAWINGS">FIG. <b>2</b>B</figref>, the optical assembly <b>180</b>A and <b>180</b>B includes a suitable display matrix <b>170</b> of any suitable type, such as a liquid crystal display (LCD), an organic light-emitting diode (OLED) display, or any other such display. The optical assembly <b>180</b>A and <b>180</b>B also includes an optical layer or layers <b>176</b>, which can include lenses, optical coatings, prisms, mirrors, waveguides, optical strips, and other optical components in any combination.

0061The optical layers <b>176</b>A-N can include a prism having a suitable size and configuration and including a first surface for receiving light from display matrix and a second surface for emitting light to the eye of the user. The prism of the optical layers <b>176</b>A-N extends over all or at least a portion of the respective apertures <b>175</b>A and <b>175</b>B formed in the left and right rims <b>107</b>A-B to permit the user to see the second surface of the prism when the eye of the user is viewing through the corresponding left and right rims <b>107</b>A-B. The first surface of the prism of the optical layers <b>176</b>A-N faces upwardly from the frame <b>105</b> and the display matrix overlies the prism so that photons and light emitted by the display matrix impinge the first surface. The prism is sized and shaped so that the light is refracted within the prism and is directed towards the eye of the user by the second surface of the prism of the optical layers <b>176</b>A-N. In this regard, the second surface of the prism of the optical layers <b>176</b>A-N can be convex to direct the light towards the center of the eye. The prism can optionally be sized and shaped to magnify the image projected by the display matrix <b>170</b>, and the light travels through the prism so that the image viewed from the second surface is larger in one or more dimensions than the image emitted from the display matrix <b>170</b>.

0062In another example, the image display device of optical assembly <b>180</b>A and <b>180</b>B includes a projection image display as shown in <figref idref="DRAWINGS">FIG. <b>2</b>C</figref>. The optical assembly <b>180</b>A and <b>180</b>B includes a laser projector <b>150</b>, which is a three-color laser projector using a scanning mirror or galvanometer. During operation, an optical source such as a laser projector <b>150</b> is disposed in or on one of the temples <b>125</b>A and <b>125</b>B of the eyewear device <b>100</b>. Optical assembly <b>180</b>A and <b>180</b>B includes one or more optical strips <b>155</b>A-N spaced apart across the width of the lens of the optical assembly <b>180</b>A and <b>180</b>B or across a depth of the lens between the front surface and the rear surface of the lens.

0063As the photons projected by the laser projector <b>150</b> travel across the lens of the optical assembly <b>180</b>A and <b>180</b>B, the photons encounter the optical strips <b>155</b>A-N. When a photon encounters an optical strip, the photon is either redirected towards the user's eye, or it passes to the next optical strip. A combination of modulation of laser projector <b>150</b>, and modulation of optical strips, may control specific photons or beams of light. In an example, a processor controls optical strips <b>155</b>A-N by initiating mechanical, acoustic, or electromagnetic signals. Although shown as having two optical assemblies <b>180</b>A and <b>180</b>B, the eyewear device <b>100</b> can include other arrangements, such as a single or three optical assemblies, or the optical assembly <b>180</b>A and <b>180</b>B may have a different arrangement depending on the application or intended user of the eyewear device <b>100</b>.

0064As further shown in <figref idref="DRAWINGS">FIGS. <b>2</b>B and <b>2</b>C</figref>, the electronic housings <b>110</b>A and <b>110</b>B may be integrated into the frame <b>105</b> on the respective lateral sides <b>170</b>A and <b>170</b>B (as illustrated) or implemented as separate components attached to the frame <b>105</b> on the respective sides <b>170</b>A and <b>170</b>B. Alternatively, the electronic housings <b>110</b>A and <b>110</b>B may be integrated into temples <b>125</b>A and <b>125</b>B attached to the frame <b>105</b>.

0065In one example, the image display includes a first (left) image display and a second (right) image display. Eyewear device <b>100</b> includes first and second apertures <b>175</b>A and <b>175</b>B which hold a respective first and second optical assembly <b>180</b>A and <b>180</b>B. The first optical assembly <b>180</b>A includes the first image display (e.g., a display matrix <b>170</b>A of <figref idref="DRAWINGS">FIG. <b>2</b>B</figref>; or optical strips <b>155</b>A-N′ and a projector <b>150</b>A of <figref idref="DRAWINGS">FIG. <b>2</b>C</figref>). The second optical assembly <b>180</b>B includes the second image display e.g., a display matrix <b>170</b>B of <figref idref="DRAWINGS">FIG. <b>2</b>B</figref>; or optical strips <b>155</b>A-N″ and a projector <b>150</b>B of <figref idref="DRAWINGS">FIG. <b>2</b>C</figref>).

0066<figref idref="DRAWINGS">FIG. <b>3</b></figref> shows a rear perspective sectional view of the eyewear device of <figref idref="DRAWINGS">FIG. <b>2</b>A</figref> depicting an infrared camera <b>220</b>, a frame front <b>330</b>, a frame back <b>335</b>, and a circuit board. The upper portion of the left rim <b>107</b>A of the frame <b>105</b> of the eyewear device <b>100</b> includes a frame front <b>330</b> and a frame back <b>335</b>. The frame front <b>330</b> includes a front-facing side configured to face outward away from the eye of the user. The frame back <b>335</b> includes a rear-facing side configured to face inward toward the eye of the user. An opening for the infrared camera <b>220</b> is formed on the frame front <b>330</b>.

0067As shown in the encircled cross-section <b>4</b>-<b>4</b> of the upper middle portion of the left rim <b>107</b>A of the frame <b>105</b>, a circuit board, which is a flexible printed circuit board (PCB) <b>340</b>, is sandwiched between the frame front <b>330</b> and the frame back <b>335</b>. Also shown in further detail is the attachment of the left electronic housing <b>110</b>A to the left temple <b>325</b>A via a left hinge <b>326</b>A. In some examples, components of the depth sensor <b>213</b>, including the infrared camera <b>220</b>, the flexible PCB <b>340</b>, or other electrical connectors or contacts may be located on the left temple <b>325</b>A or the left hinge <b>326</b>A.

0068In an example, the left electronic housing <b>110</b>A includes an electronic housing body <b>311</b>, an electronic housing cap <b>312</b>, an inward facing surface <b>391</b> and an outward facing surface <b>392</b> (labeled, but not visible). Disposed inside the left electronic housing <b>110</b>A are various interconnected circuit boards, such as PCBs or flexible PCBs, which include controller circuits for charging a battery, inwards facing light emitting diodes (LEDs), and outwards (forward) facing LEDs. Although shown as being formed on the circuit boards of the left rim <b>107</b>A, the depth sensor <b>213</b>, including the infrared emitter <b>215</b> and the infrared camera <b>220</b>, can be formed on the circuit boards of the right rim <b>107</b>B to captured infrared images utilized in the generation of three-dimensional depth images or depth videos, for example, in combination with right visible light camera <b>114</b>B.

0069<figref idref="DRAWINGS">FIG. <b>4</b></figref> is a cross-sectional view through the infrared camera <b>220</b> and the frame corresponding to the encircled cross-section <b>4</b>-<b>4</b> of the eyewear device of <figref idref="DRAWINGS">FIG. <b>3</b></figref>. Various layers of the eyewear device <b>100</b> are visible in the cross-section of <figref idref="DRAWINGS">FIG. <b>4</b></figref>. As shown, the flexible PCB <b>340</b> is disposed on the frame back <b>335</b> and connected to the frame front <b>330</b>. The infrared camera <b>220</b> is disposed on the flexible PCB <b>340</b> and covered by an infrared camera cover lens <b>445</b>. For example, the infrared camera <b>220</b> is reflowed to the back of the flexible PCB <b>340</b>. Reflowing attaches the infrared camera <b>220</b> to electrical contact pad(s) formed on the back of the flexible PCB <b>340</b> by subjecting the flexible PCB <b>340</b> to controlled heat which melts a solder paste to connect the two components. In one example, reflowing is used to surface mount the infrared camera <b>220</b> on the flexible PCB <b>340</b> and electrically connect the two components. However, through-holes can be used to connect leads from the infrared camera <b>220</b> to the flexible PCB <b>340</b> via interconnects, for example.

0070The frame front <b>330</b> includes an infrared camera opening <b>450</b> for the infrared camera cover lens <b>445</b>. The infrared camera opening <b>450</b> is formed on a front-facing side of the frame front <b>330</b> that is configured to face outwards away from the eye of the user and towards a scene being observed by the user. In the example, the flexible PCB <b>340</b> can be connected to the frame back <b>335</b> via a flexible PCB adhesive <b>460</b>. The infrared camera cover lens <b>445</b> can be connected to the frame front <b>330</b> via infrared camera cover lens adhesive <b>455</b>. The connection can be indirect via intervening components.

0071<figref idref="DRAWINGS">FIG. <b>5</b></figref> shows a rear perspective view of the eyewear device of <figref idref="DRAWINGS">FIG. <b>2</b>A</figref>. The eyewear device <b>100</b> includes an infrared emitter <b>215</b>, infrared camera <b>220</b>, a frame front <b>330</b>, a frame back <b>335</b>, and a circuit board <b>340</b>. As in <figref idref="DRAWINGS">FIG. <b>3</b></figref>, it can be seen in <figref idref="DRAWINGS">FIG. <b>5</b></figref> that the upper portion of the left rim of the frame of the eyewear device <b>100</b> includes the frame front <b>330</b> and the frame back <b>335</b>. An opening for the infrared emitter <b>215</b> is formed on the frame front <b>330</b>.

0072As shown in the encircled cross-section <b>6</b>-<b>6</b> in the upper middle portion of the left rim of the frame, a circuit board, which is a flexible PCB <b>340</b>, is sandwiched between the frame front <b>330</b> and the frame back <b>335</b>. Also shown in further detail is the attachment of the left electronic housing <b>110</b>A to the left temple <b>325</b>A via the left hinge <b>326</b>A. In some examples, components of the depth sensor <b>213</b>, including the infrared emitter <b>215</b>, the flexible PCB <b>340</b>, or other electrical connectors or contacts may be located on the left temple <b>325</b>A or the left hinge <b>326</b>A.

0073<figref idref="DRAWINGS">FIG. <b>6</b></figref> is a cross-sectional view through the infrared emitter <b>215</b> and the frame corresponding to the encircled cross-section <b>6</b>-<b>6</b> of the eyewear device of <figref idref="DRAWINGS">FIG. <b>5</b></figref>. Multiple layers of the eyewear device <b>100</b> are illustrated in the cross-section of <figref idref="DRAWINGS">FIG. <b>6</b></figref>, as shown the frame <b>105</b> includes the frame front <b>330</b> and the frame back <b>335</b>. The flexible PCB <b>340</b> is disposed on the frame back <b>335</b> and connected to the frame front <b>330</b>. The infrared emitter <b>215</b> is disposed on the flexible PCB <b>340</b> and covered by an infrared emitter cover lens <b>645</b>. For example, the infrared emitter <b>215</b> is reflowed to the back of the flexible PCB <b>340</b>. Reflowing attaches the infrared emitter <b>215</b> to contact pad(s) formed on the back of the flexible PCB <b>340</b> by subjecting the flexible PCB <b>340</b> to controlled heat which melts a solder paste to connect the two components. In one example, reflowing is used to surface mount the infrared emitter <b>215</b> on the flexible PCB <b>340</b> and electrically connect the two components. However, through-holes can be used to connect leads from the infrared emitter <b>215</b> to the flexible PCB <b>340</b> via interconnects, for example.

0074The frame front <b>330</b> includes an infrared emitter opening <b>650</b> for the infrared emitter cover lens <b>645</b>. The infrared emitter opening <b>650</b> is formed on a front-facing side of the frame front <b>330</b> that is configured to face outwards away from the eye of the user and towards a scene being observed by the user. In the example, the flexible PCB <b>340</b> can be connected to the frame back <b>335</b> via the flexible PCB adhesive <b>460</b>. The infrared emitter cover lens <b>645</b> can be connected to the frame front <b>330</b> via infrared emitter cover lens adhesive <b>655</b>. The coupling can also be indirect via intervening components.

0075<figref idref="DRAWINGS">FIG. <b>7</b></figref> depicts an example of an emitted pattern of infrared light <b>781</b> emitted by an infrared emitter <b>215</b> of the depth sensor <b>213</b>. As shown, reflection variations of the emitted pattern of infrared light <b>782</b> are captured by the infrared camera <b>220</b> of the depth sensor <b>213</b> of the eyewear device <b>100</b> as an infrared image. The reflection variations of the emitted pattern of infrared light <b>782</b> is utilized to measure depth of pixels in a raw image (e.g., left raw image) to generate three-dimensional depth images, such as the initial depth images of a sequence of initial depth images (e.g., in an initial video).

0076Depth sensor <b>213</b> in the example includes the infrared emitter <b>215</b> to project a pattern of infrared light and the infrared camera <b>220</b> to capture infrared images of distortions of the projected infrared light by objects or object features in a space, shown as scene <b>715</b> being observed by the wearer of the eyewear device <b>100</b>. The infrared emitter <b>215</b>, for example, may blast infrared light <b>781</b> which falls on objects or object features within the scene <b>715</b> like a sea of dots. In some examples, the infrared light is emitted as a line pattern, a spiral, or a pattern of concentric rings or the like. Infrared light is typically not visible to the human eye. The infrared camera <b>220</b> is like a standard red, green, and blue (RGB) camera but receives and captures images of light in the infrared wavelength range. For depth sensing, the infrared camera <b>220</b> is coupled to an image processor (element <b>912</b> of <figref idref="DRAWINGS">FIG. <b>9</b></figref>) and the camera misalignment compensation programming (element <b>945</b>) that judge time of flight based on the captured infrared image of the infrared light. For example, the distorted dot pattern <b>782</b> in the captured infrared image can then be processed by an image processor to determine depth from the displacement of dots. Typically, nearby objects or object features have a pattern with dots spread further apart and far away objects have a denser dot pattern. The foregoing functionality can be embodied in programming instructions of camera misalignment compensation system programming or application (element <b>945</b>) found in one or more components of the system.

0077<figref idref="DRAWINGS">FIG. <b>8</b>A</figref> depicts an example of infrared light captured by the infrared camera <b>220</b> of the depth sensor <b>213</b> with a left infrared camera field of view <b>812</b>. Infrared camera <b>220</b> captures reflection variations in the emitted pattern of infrared light <b>782</b> in the three-dimensional scene <b>715</b> as an infrared image <b>859</b>. As further shown, visible light is captured by the left visible light camera <b>114</b>A with a left visible light camera field of view <b>111</b>A as a left raw image <b>858</b>A. Based on the infrared image <b>859</b> and left raw image <b>858</b>A, the three-dimensional initial depth image of the three-dimensional scene <b>715</b> is generated.

0078<figref idref="DRAWINGS">FIG. <b>8</b>B</figref> depicts an example of visible light captured by the left visible light camera <b>114</b>A and visible light captured with a right visible light camera <b>114</b>B. Visible light is captured by the left visible light camera <b>114</b>A with a left visible light camera field of view <b>111</b>A as a left raw image <b>858</b>A. Visible light is captured by the right visible light camera <b>114</b>B with a right visible light camera field of view <b>111</b>B as a right raw image <b>858</b>B. Based on the left raw image <b>858</b>A and the right raw image <b>858</b>B, the three-dimensional initial depth image of the three-dimensional scene <b>715</b> is generated.

0079<figref idref="DRAWINGS">FIG. <b>8</b>C</figref> depicts initial images captured using visible light cameras. A left visible light camera (e.g., camera <b>114</b>A) captures a left raw image <b>800</b><i>a </i>including an image feature <b>802</b><i>a </i>of a feature within a scene and a right visible light camera (e.g., camera <b>114</b>B) captures a right raw image <b>800</b><i>b </i>including an image feature <b>802</b><i>b </i>of the same feature within the scene. Misalignment of the cameras (e.g., due to manufacturing tolerances) results in the image feature <b>802</b><i>a </i>being slightly offset in the Y-direction (i.e., vertical direction) with respect to the image feature <b>802</b><i>b. </i>

0080<figref idref="DRAWINGS">FIG. <b>8</b>D</figref> depicts a rectified and compensated left image <b>804</b><i>a </i>and a rectified and compensated right image <b>804</b><i>b</i>. A transformation function <b>965</b> rectifies the images and the camera misalignment and compensation system described herein compensates for misalignment between the rectified left raw image <b>800</b><i>a </i>and the right raw image <b>800</b><i>b </i>to obtain the rectified and compensated left image <b>804</b><i>a </i>and right image <b>804</b><i>b</i>. As seen in <figref idref="DRAWINGS">FIG. <b>8</b>D</figref>, the image feature <b>802</b><i>a </i>and <b>802</b><i>b </i>lie on the same raster line <b>806</b>, which facilitates matching image features to determine offset in the horizontal direction for use in three-dimensional rendering.

0081<figref idref="DRAWINGS">FIG. <b>8</b>E</figref> depicts a graph <b>808</b> showing readout times for image rows for a sensor/camera having a rolling shutter in accordance with the prior art. As seen in <figref idref="DRAWINGS">FIG. <b>8</b>E</figref>, in a rolling shutter camera system, image rows are read out at different times (represented by the solid vertical bars in the graph <b>808</b>.

0082<figref idref="DRAWINGS">FIG. <b>8</b>F</figref> depicts images captured by a stereoscopic camera system in a static system (e.g., the cameras and the scene being imaged are not moving in relation to one another) where the cameras of the camera system have different pitch angles. As illustrated in <figref idref="DRAWINGS">FIG. <b>8</b>F</figref>, the orientation of the left camera (e.g., camera <b>114</b>A) has a pitch offset with respect to the orientation of the right camera (e.g., camera <b>114</b>B). The pitch offset results in the image feature <b>802</b><i>a </i>being above a raster line <b>805</b> and the image feature <b>802</b><i>b </i>being below the raster line. Due to the rolling shutter illustrated in <figref idref="DRAWINGS">FIG. <b>8</b>E</figref>, this may result in the image features being read out of their respective cameras at different times with respect to their expected readouts after synchronization.

0083<figref idref="DRAWINGS">FIG. <b>8</b>G</figref> depicts images captured by a stereoscopic camera system in a dynamic system (e.g., the cameras and/or the scene being imaged are moving in relation to one another) where the cameras of the camera system have different pitch angles (e.g., the same pitch angle difference as seen in <figref idref="DRAWINGS">FIG. <b>8</b>F</figref>). As illustrated in <figref idref="DRAWINGS">FIG. <b>8</b>G</figref>, the orientation of the left camera (e.g., camera <b>114</b>A) has a pitch offset with respect to the orientation of the right camera (e.g., camera <b>114</b>B). The pitch offset and the dynamic movement results in the image feature <b>802</b><i>a </i>being even farther below the raster line <b>806</b> than in <figref idref="DRAWINGS">FIG. <b>8</b>F</figref>. Due to the rolling shutter illustrated in <figref idref="DRAWINGS">FIG. <b>8</b>E</figref>, this may result in the image features being read out of their respective cameras at an even greater amount of times with respect to their expected readouts after synchronization. The amount of time may be greater than tolerances built into the system, thereby preventing matching of features for three-dimensional rendering. In an example, a pitch offset of 3.56 degrees may result in a range of 40-75 pixels. Examples described herein adjust the synchronization to account for the pitch offset in order to remove differences in readout times, thus improving the systems ability to match features in stereoscopic images.

0084<figref idref="DRAWINGS">FIG. <b>9</b></figref> is a high-level functional block diagram of an example camera misalignment compensation system <b>900</b>, which includes a wearable device (e.g., the eyewear device <b>100</b>), a mobile device <b>990</b>, and a server system <b>998</b> connected via various networks. Eyewear device <b>100</b> includes an input parameter processor and a depth-capturing camera, such as at least one of the visible light cameras <b>114</b>A and <b>114</b>B; and the depth sensor <b>213</b>, shown as infrared emitter <b>215</b> and infrared camera <b>220</b>. The depth-capturing camera can alternatively include at least two visible light cameras <b>114</b>A and <b>114</b>B (one associated with the left lateral side <b>170</b>A and one associated with the right lateral side <b>170</b>B). Depth-capturing camera generates initial depth images <b>961</b>A-N of initial video <b>960</b>, which are rendered three-dimensional (3D) models that are texture mapped images of red, green, and blue (RGB) imaged scenes. A transformation function <b>965</b> within the wearable device rectifies the initial images, e.g., to facilitate matching of features and to format the images for viewing.

0085Mobile device <b>990</b> may be a smartphone, tablet, laptop computer, access point, or any other such device capable of connecting with eyewear device <b>100</b> using both a low-power wireless connection <b>925</b> and a high-speed wireless connection <b>937</b>. Mobile device <b>990</b> is connected to server system <b>998</b> and network <b>995</b>. The network <b>995</b> may include any combination of wired and wireless connections.

0086Eyewear device <b>100</b> further includes two image displays of the optical assembly <b>180</b>A and <b>180</b>B (one associated with the left lateral side <b>170</b>A and one associated with the right lateral side <b>170</b>B). Eyewear device <b>100</b> also includes image display driver <b>942</b>, image processor <b>912</b>, low-power circuitry <b>920</b>, and high-speed circuitry <b>930</b>. Image display of optical assembly <b>180</b>A and <b>180</b>B are for presenting images and videos, which can include a sequence of depth images, such as the initial depth images <b>961</b>A-N from the initial video <b>960</b>. Image display driver <b>942</b> is coupled to the image display of optical assembly <b>180</b>A and <b>180</b>B to control the image display of optical assembly <b>180</b>A and <b>180</b>B to present the video including images, such as, for example, the initial depth images <b>961</b>A-N of initial video <b>960</b>. Eyewear device <b>100</b> further includes a user input device <b>991</b> (e.g., touch sensor) to receive input and selections from a user.

0087The components shown in <figref idref="DRAWINGS">FIG. <b>9</b></figref> for the eyewear device <b>100</b> are located on one or more circuit boards, for example a PCB or flexible PCB, in the rims or temples. Alternatively, or additionally, the depicted components can be in the electronic housings, frames, hinges, or bridge of the eyewear device <b>100</b>. Left and right visible light cameras <b>114</b>A and <b>114</b>B can include digital camera elements such as a complementary metal-oxide-semiconductor (CMOS) image sensor, charge coupled device, a lens, or any other respective visible or light capturing elements that may be used to capture data, including images of scenes with unknown objects.

0088Eyewear device <b>100</b> includes a memory <b>934</b> which includes input parameter programming and camera misalignment compensation programming <b>945</b> to perform a subset or all the functions described herein for camera misalignment compensation. As shown, memory <b>934</b> further includes a left raw image <b>858</b>A captured by left visible light camera <b>114</b>A, a right raw image <b>858</b>B captured by right visible light camera <b>114</b>B, and an infrared image <b>859</b> captured by infrared camera <b>220</b> of the depth sensor <b>213</b>.

0089As shown, eyewear device <b>100</b> includes an orientation sensor, which includes, for example, an inertial measurement unit (IMU) <b>972</b> as depicted. Generally, an inertial measurement unit <b>972</b> is an electronic device that measures and reports a body's specific force, angular rate, and sometimes the magnetic field surrounding the body, using a combination of accelerometers and gyroscopes, sometimes also magnetometers. In this example, the inertial measurement unit <b>972</b> determines a head orientation of a wearer of the eyewear device <b>100</b> which correlates to a camera orientation of the depth-capturing camera of the eyewear device <b>100</b> when the associated depth image is captured. The inertial measurement unit <b>972</b> works by detecting linear acceleration using one or more accelerometers and rotational rate using one or more gyroscopes. Typical configurations of inertial measurement units contain one accelerometer, gyro, and magnetometer per axis for each of the three axes: horizontal axis for left-right movement (X), vertical axis (Y) for top-bottom movement, and depth or distance axis for up-down movement (Z). The gyroscope detects the gravity vector. The magnetometer defines the rotation in the magnetic field (e.g., facing south, north, etc.) like a compass which generates a heading reference. The three accelerometers detect acceleration along the horizontal (X), vertical (Y), and depth (Z) axes defined above, which can be defined relative to the ground, the eyewear device <b>100</b>, the depth-capturing camera, or the user wearing the eyewear device <b>100</b>.

0090Memory <b>934</b> includes head orientation measurements which correspond to principal axes measurements on the horizontal axis (X axis), vertical axis (Y axis), and depth or distance axis (Z axis) as tracked (e.g., measured) by the inertial measurement unit <b>972</b>. The head orientation measurements are utilized to determine alignment of the depth-capturing camera, which can be used to identify a floor plane of the initial depth images <b>961</b>A-N. In certain applications of IMUs, the principal axes are referred to as pitch, roll, and yaw axes.

0091Memory <b>934</b> further includes multiple initial depth images <b>961</b>A-N, which are generated, via the depth-capturing camera. Memory <b>934</b> further includes an initial video <b>960</b> which includes a sequence of the initial depth images <b>961</b>A-N and associated time coordinates. A flowchart outlining functions which can be implemented in the camera misalignment compensation programming <b>945</b> is shown in <figref idref="DRAWINGS">FIG. <b>11</b></figref>.

0092As shown in <figref idref="DRAWINGS">FIG. <b>9</b></figref>, high-speed circuitry <b>930</b> includes high-speed processor <b>932</b>, memory <b>934</b>, and high-speed wireless circuitry <b>936</b>. In the example, the image display driver <b>942</b> is coupled to the high-speed circuitry <b>930</b> and operated by the high-speed processor <b>932</b> in order to drive the left and right image displays of the optical assembly <b>180</b>A and <b>180</b>B. High-speed processor <b>932</b> may be any processor capable of managing high-speed communications and operation of any general computing system needed for eyewear device <b>100</b>. High-speed processor <b>932</b> includes processing resources needed for managing high-speed data transfers on high-speed wireless connection <b>937</b> to a wireless local area network (WLAN) using high-speed wireless circuitry <b>936</b>. In some examples, the high-speed processor <b>932</b> executes an operating system such as a LINUX operating system or other such operating system of the eyewear device <b>100</b> and the operating system is stored in memory <b>934</b> for execution. In addition to any other responsibilities, the high-speed processor <b>932</b> executing a software architecture for the eyewear device <b>100</b> manages data transfers with high-speed wireless circuitry <b>936</b>. In some examples, high-speed wireless circuitry <b>936</b> is configured to implement Institute of Electrical and Electronic Engineers (IEEE) 802.11 communication standards, also referred to herein as Wi-Fi. In other examples, other high-speed communications standards may be implemented by high-speed wireless circuitry <b>936</b>.

0093Low-power wireless circuitry <b>924</b> and the high-speed wireless circuitry <b>936</b> of the eyewear device <b>100</b> can include short range transceivers (Bluetooth™) and wireless wide, local, or wide area network transceivers (e.g., cellular or Wi-Fi). Mobile device <b>990</b>, including the transceivers communicating via the low-power wireless connection <b>925</b> and high-speed wireless connection <b>937</b>, may be implemented using details of the architecture of the eyewear device <b>100</b>, as can other elements of network <b>995</b>.

0094Memory <b>934</b> includes any storage device capable of storing various data and applications, including, among other things, camera data generated by the left and right visible light cameras <b>114</b>A and <b>114</b>B, infrared camera <b>220</b>, and the image processor <b>912</b>, as well as images and videos generated for display by the image display driver <b>942</b> on the image displays of the optical assembly <b>180</b>A and <b>180</b>B. While memory <b>934</b> is shown as integrated with high-speed circuitry <b>930</b>, in other examples, memory <b>934</b> may be an independent standalone element of the eyewear device <b>100</b>. In some such examples, electrical routing lines may provide a connection through a chip that includes the high-speed processor <b>932</b> from the image processor <b>912</b> or low-power processor <b>922</b> to the memory <b>934</b>. In other examples, the high-speed processor <b>932</b> may manage addressing of memory <b>934</b> such that the low-power processor <b>922</b> will boot the high-speed processor <b>932</b> any time that a read or write operation involving memory <b>934</b> is needed.

0095As shown in <figref idref="DRAWINGS">FIG. <b>9</b></figref>, the processor <b>932</b> of the eyewear device <b>100</b> can be coupled to the depth-capturing camera (visible light cameras <b>114</b>A and <b>114</b>B; or visible light camera <b>114</b>A, infrared emitter <b>215</b>, and infrared camera <b>220</b>), the image display driver <b>942</b>, the user input device <b>991</b>, and the memory <b>934</b>. As shown in <figref idref="DRAWINGS">FIG. <b>10</b></figref>, the processor <b>1030</b> of the mobile device <b>990</b> can be coupled to the depth-capturing camera <b>1070</b>, the image display driver <b>1090</b>, the user input device <b>1091</b>, and the memory <b>1040</b>A. Eyewear device <b>100</b> can perform all or a subset of any of the following functions described below as a result of the execution of the camera misalignment compensation programming <b>945</b> in the memory <b>934</b> by the processor <b>932</b> of the eyewear device <b>100</b>. Mobile device <b>990</b> can perform all or a subset of any of the following functions described below as a result of the execution of the camera misalignment compensation programming <b>945</b> in the memory <b>1040</b>A by the processor <b>1030</b> of the mobile device <b>990</b>. Functions can be divided in the camera misalignment compensation system <b>900</b>, such that the eyewear device <b>100</b> generates the initial depth images <b>961</b>A-N from the initial video <b>960</b>, but the mobile device <b>990</b> performs the remainder of the image processing on the initial depth images <b>961</b>A-N from the initial video <b>960</b> to compensation for misalignment of the cameras.

0096In one example of the camera misalignment compensation system <b>900</b>, the processor comprises a first processor <b>932</b> and a second processor <b>1030</b>. The memory comprises a first memory <b>934</b> and a second memory <b>1040</b>A. The eyewear device <b>100</b> includes a first network communication <b>924</b> or <b>936</b> interface for communication over a network <b>925</b> or <b>937</b> (e.g., a wireless short-range network or a wireless local area network), the first processor <b>932</b> coupled to the first network communication interface <b>924</b> or <b>936</b>, and the first memory <b>934</b> accessible to the first processor <b>932</b>. Eyewear device <b>100</b> further includes camera misalignment compensation programming <b>945</b> in the first memory <b>934</b>. Execution of the camera misalignment compensation programming <b>945</b> by the first processor <b>932</b> configures the eyewear device <b>100</b> to perform the function to capture, via the depth-capturing camera, images.

0097The camera misalignment compensation system <b>900</b> further comprises a host computer, such as the mobile device <b>990</b>, coupled to the eyewear device <b>100</b> over the network <b>925</b> or <b>937</b>. The host computer includes a second network communication interface <b>1010</b> or <b>1020</b> for communication over the network <b>925</b> or <b>937</b>, the second processor <b>1030</b> coupled to the second network communication interface <b>1010</b> or <b>1020</b>, and the second memory <b>1040</b>A accessible to the second processor <b>1030</b>. Host computer further includes camera misalignment compensation programming <b>945</b> in the second memory <b>1040</b>A.

0098Execution of the camera misalignment compensation programming <b>945</b> by the second processor <b>1030</b> configures the host computer to perform the functions to receive, via the second network communication interface <b>1010</b> or <b>1020</b>, the captured images over the network from the eyewear device <b>100</b>. Execution of the camera misalignment compensation programming <b>945</b> by the second processor <b>1030</b> configures the host computer to compensate for misalignment of the cameras and present, via the image display <b>1080</b>, the compensated images.

0099In one example, the depth-capturing camera of the eyewear device <b>100</b> includes the at least two visible light cameras comprised of a left visible light camera <b>114</b>A with a left field of view <b>111</b>A and a right visible light camera <b>114</b>B with a right field of view <b>111</b>B. The left field of view <b>111</b>A and the right field of view <b>111</b>B have an overlapping field of view <b>813</b> (see <figref idref="DRAWINGS">FIG. <b>8</b>B</figref>). The depth-capturing camera <b>1070</b> of the mobile device <b>990</b> can be similarly structured.

0100Generating, via the depth-capturing camera, the initial video <b>960</b> including the sequence of initial depth images <b>961</b>A-N and associated time coordinates can include all or a subset of the following functions. First, capturing, via the left visible light camera <b>114</b>A, a left raw image <b>858</b>A that includes a left matrix of pixels. Second, capturing, via the right visible light camera <b>114</b>B, a right raw image <b>858</b>B that includes a right matrix of pixels. Third, creating a left rectified image <b>969</b>A from the left raw image <b>858</b>A and a right rectified image <b>969</b>B from the right raw image <b>858</b>B that align the left and right raw images <b>858</b>A-B and remove distortion from a respective lens (e.g., at the edges of the lens from vignetting) of each of the left and right visible light cameras <b>114</b>A and <b>114</b>B. Fourth, extracting an image disparity <b>970</b> by correlating pixels in the left rectified image <b>969</b>A with the right rectified image <b>969</b>B to calculate a disparity for each of the correlated pixels. Fifth, calculating the Z location coordinate of vertices of the initial depth image <b>961</b>A based on at least the extracted image disparity <b>970</b> for each of the correlated pixels. Sixth, ordering each of the generated initial depth images <b>961</b>A-N in the sequence from the initial video <b>960</b> based on a timestamp that is captured when the left raw image <b>858</b>A and the right raw image <b>858</b>B are captured and setting an associated respective time coordinate of the respective initial depth image <b>961</b>A-N to the timestamp.

0101In an example, the depth-capturing camera of the eyewear device <b>100</b> includes the at least one visible light camera <b>114</b>A and the depth sensor <b>213</b> (e.g., infrared emitter <b>215</b> and infrared camera <b>220</b>). The at least one visible light camera <b>114</b>A and the depth sensor <b>213</b> have a substantially overlapping field of view <b>812</b> (see <figref idref="DRAWINGS">FIG. <b>8</b>A</figref>). The depth sensor <b>213</b> includes an infrared emitter <b>215</b> and an infrared camera <b>220</b>. The infrared emitter <b>215</b> is connected to the frame <b>105</b> or the temple <b>125</b>A and <b>125</b>B to emit a pattern of infrared light. The infrared camera <b>220</b> is connected to the frame <b>105</b> or the temple <b>125</b>A and <b>125</b>B to capture reflection variations in the emitted pattern of infrared light. The depth-capturing camera <b>1070</b> of the mobile device <b>990</b> can be similarly structured.

0102Generating, via the depth-capturing camera, the initial depth image <b>961</b>A can include all or a subset of the following functions. First, capturing, via the at least one visible light camera <b>114</b>A, a raw image <b>858</b>A. Second, emitting, via the infrared emitter <b>215</b>, a pattern of infrared light <b>781</b> on a plurality of objects or object features located in a scene <b>715</b> that are reached by the emitted infrared light <b>781</b>. Third, capturing, via the infrared camera <b>220</b>, an infrared image <b>859</b> of reflection variations of the emitted pattern of infrared light <b>782</b> on the plurality of objects or object features. Fourth, computing a respective depth from the depth-capturing camera to the plurality of objects or object features, based on the infrared image <b>859</b> of reflection variations. Fifth, correlating objects or object features in the infrared image <b>859</b> of reflection variations with the raw image <b>858</b>A. Sixth, calculating the Z location coordinate of vertices of the initial depth image <b>961</b>A based on, at least, the computed respective depth.

0103In one example, the user input device <b>991</b>, <b>1091</b> includes a touch sensor including an input surface and a sensor array that is coupled to the input surface to receive at least one finger contact inputted from a user. User input device <b>991</b>, <b>1091</b> further includes a sensing circuit integrated into or connected to the touch sensor and connected to the processor <b>932</b>, <b>1030</b>. The sensing circuit is configured to measure voltage to track the at least one finger contact on the input surface. The function of receiving, via the user input device <b>991</b>, <b>1091</b>, input parameter identification from the user includes receiving, on the input surface of the touch sensor, the at least one finger contact inputted from the user.

0104A touch-based user input device <b>991</b> can be integrated into the eyewear device <b>100</b>. As noted above, eyewear device <b>100</b> includes an electronic housing <b>110</b>A and <b>110</b>B integrated into or connected to the frame <b>105</b> on the lateral side <b>170</b>A and <b>170</b>B of the eyewear device <b>100</b>. The frame <b>105</b>, the temple <b>125</b>A and <b>125</b>B, or the electronic housing <b>110</b>A and <b>110</b>B includes a circuit board that includes the touch sensor. The circuit board includes a flexible printed circuit board. The touch sensor is disposed on the flexible printed circuit board. The sensor array is a capacitive array or a resistive array. The capacitive array or the resistive array includes a grid that forms a two-dimensional rectangular coordinate system to track X and Y axes location coordinates.

0105Server system <b>998</b> may be one or more computing devices as part of a service or network computing system, for example, that include a processor, a memory, and network communication interface to communicate over the network <b>995</b> with the mobile device <b>990</b> and eyewear device <b>100</b>. Eyewear device <b>100</b> is connected with a host computer. For example, the eyewear device <b>100</b> is paired with the mobile device <b>990</b> via the high-speed wireless connection <b>937</b> or connected to the server system <b>998</b> via the network <b>995</b>.

0106Output components of the eyewear device <b>100</b> include visual components, such as the left and right image displays of optical assembly <b>180</b>A and <b>180</b>B as described in <figref idref="DRAWINGS">FIGS. <b>2</b>B and <b>2</b>C</figref> (e.g., a display such as a liquid crystal display (LCD), a plasma display panel (PDP), a light emitting diode (LED) display, a projector, or a waveguide). Left and right image displays of optical assembly <b>180</b>A and <b>180</b>B can present the initial video <b>960</b> including the sequence of initial depth images <b>961</b>A-N. The image displays of the optical assembly <b>180</b>A and <b>180</b>B are driven by the image display driver <b>942</b>. Image display driver <b>942</b> is coupled to the image display to control the image display to present the initial video <b>960</b>. The output components of the eyewear device <b>100</b> further include acoustic components (e.g., speakers), haptic components (e.g., a vibratory motor), other signal generators, and so forth. The input components of the eyewear device <b>100</b>, the mobile device <b>990</b>, and server system <b>998</b>, may include alphanumeric input components (e.g., a keyboard, a touch screen configured to receive alphanumeric input, a photo-optical keyboard, or other alphanumeric input components), point-based input components (e.g., a mouse, a touchpad, a trackball, a joystick, a motion sensor, or other pointing instruments), tactile input components (e.g., a physical button, a touch screen that provides location and force of touches or touch gestures, or other tactile input components), audio input components (e.g., a microphone), biometric components (e.g., a heart rate monitor) and the like.

0107Eyewear device <b>100</b> may optionally include additional peripheral device elements. Such peripheral device elements may include biometric sensors, additional sensors, or display elements integrated with eyewear device <b>100</b>. For example, peripheral device elements may include any I/O components including output components, motion components, position components, or any other such elements described herein.

0108For example, the biometric components include components to detect expressions (e.g., hand expressions, facial expressions, vocal expressions, body gestures, or eye tracking), measure biosignals (e.g., blood pressure, heart rate, body temperature, perspiration, or brain waves), identify a person (e.g., voice identification, retinal identification, facial identification, fingerprint identification, or electroencephalogram based identification), and the like. The motion components include acceleration sensor components (e.g., accelerometer), gravitation sensor components, rotation sensor components (e.g., gyroscope), and so forth. The position components include location sensor components to generate location coordinates (e.g., a Global Positioning System (GPS) receiver component), Wi-Fi or Bluetooth™ transceivers to generate positioning system coordinates, altitude sensor components (e.g., altimeters or barometers that detect air pressure from which altitude may be derived), orientation sensor components (e.g., magnetometers), and the like. Such positioning system coordinates can also be received over wireless connections <b>925</b> and <b>937</b> from the mobile device <b>990</b> via the low-power wireless circuitry <b>924</b> or high-speed wireless circuitry <b>936</b>.

0109<figref idref="DRAWINGS">FIG. <b>10</b></figref> is a high-level functional block diagram of an example of a mobile device <b>990</b>. Mobile device <b>990</b> includes a user input device <b>1091</b> and an input parameter processor <b>1092</b> to receive user selections. Mobile device <b>990</b> includes a flash memory <b>1040</b>A which includes camera misalignment compensation programming <b>945</b> to perform all or a subset of the functions described herein for camera misalignment compensation. As shown, memory <b>1040</b>A further includes a left raw image <b>858</b>A captured by left visible light camera <b>114</b>A, a right raw image <b>858</b>B captured by right visible light camera <b>114</b>B, and an infrared image <b>859</b> captured by infrared camera <b>220</b> of the depth sensor <b>213</b>. Mobile device <b>1090</b> can include a depth-capturing camera <b>1070</b> that comprises at least two visible light cameras (first and second visible light cameras with overlapping fields of view) or at least on visible light camera and a depth sensor with substantially overlapping fields of view like the eyewear device <b>100</b>. When the mobile device <b>990</b> includes components like the eyewear device <b>100</b>, such as the depth-capturing camera, the left raw image <b>858</b>A, the right raw image <b>858</b>B, and the infrared image <b>859</b> can be captured via the depth-capturing camera <b>1070</b> of the mobile device <b>990</b>. A transformation function <b>965</b> within the mobile device rectifies the initial images, e.g., to facilitate matching of features and to format the images for viewing.

0110Memory <b>1040</b>A further includes multiple initial depth images <b>961</b>A-N, which are generated, via the depth-capturing camera of the eyewear device <b>100</b> or via the depth-capturing camera <b>1070</b> of the mobile device <b>990</b> itself. Memory <b>1040</b>A further includes an initial video <b>960</b> which includes a sequence of the initial depth images <b>961</b>A-N and associated time coordinates. Flowcharts outlining functions which can be implemented in the camera misalignment compensation programming <b>945</b> are shown in <figref idref="DRAWINGS">FIGS. <b>11</b>A-<b>11</b>C</figref>.

0111As shown, the mobile device <b>990</b> includes an image display <b>1080</b>, an image display driver <b>1090</b> to control the image display, and a user input device <b>1091</b> like the eyewear device <b>100</b>. In the example of <figref idref="DRAWINGS">FIG. <b>10</b></figref>, the image display <b>1080</b> and user input device <b>1091</b> are integrated together into a touch screen display.

0112Examples of touch screen type mobile devices that may be used include (but are not limited to) a smart phone, a personal digital assistant (PDA), a tablet computer, a laptop computer, or other portable device. However, the structure and operation of the touch screen type devices is provided by way of example; and the subject technology as described herein is not intended to be limited thereto. For purposes of this discussion, <figref idref="DRAWINGS">FIG. <b>10</b></figref> therefore provides block diagram illustrations of the example mobile device <b>990</b> having a touch screen display for displaying content and receiving user input as (or as part of) the user interface.

0113As shown in <figref idref="DRAWINGS">FIG. <b>10</b></figref>, the mobile device <b>990</b> includes at least one digital transceiver (XCVR) <b>1010</b>, shown as WWAN XCVRs, for digital wireless communications via a wide area wireless mobile communication network. The mobile device <b>990</b> also includes additional digital or analog transceivers, such as short range XCVRs <b>1020</b> for short-range network communication, such as via NFC, VLC, DECT, ZigBee, Bluetooth™, or Wi-Fi. For example, short range XCVRs <b>1020</b> may take the form of any available two-way wireless local area network (WLAN) transceiver of a type that is compatible with one or more standard protocols of communication implemented in wireless local area networks, such as one of the Wi-Fi standards under IEEE 802.11 and WiMAX.

0114To generate location coordinates for positioning of the mobile device <b>990</b>, the mobile device <b>990</b> can include a global positioning system (GPS) receiver. Alternatively, or additionally the mobile device <b>990</b> can utilize either or both the short range XCVRs <b>1020</b> and WWAN XCVRs <b>1010</b> for generating location coordinates for positioning. For example, cellular network, Wi-Fi, or Bluetooth™ based positioning systems can generate very accurate location coordinates, particularly when used in combination. Such location coordinates can be transmitted to the eyewear device over one or more network connections via XCVRs <b>1010</b>, <b>1020</b>.

0115The transceivers <b>1010</b>, <b>1020</b> (network communication interface) conform to one or more of the various digital wireless communication standards utilized by modern mobile networks. Examples of WWAN transceivers <b>1010</b> include (but are not limited to) transceivers configured to operate in accordance with Code Division Multiple Access (CDMA) and 3rd Generation Partnership Project (3GPP) network technologies including, for example and without limitation, 3GPP type 2 (or 3GPP2) and LTE, at times referred to as “4G.” For example, the transceivers <b>1010</b>, <b>1020</b> provide two-way wireless communication of information including digitized audio signals, still image and video signals, web page information for display as well as web related inputs, and various types of mobile message communications to/from the mobile device <b>990</b>.

0116Several of these types of communications through the transceivers <b>1010</b>, <b>1020</b> and a network, as discussed previously, relate to protocols and procedures in support of communications with the eyewear device <b>100</b> or the server system <b>998</b>, such as transmitting left raw image <b>858</b>A, right raw image <b>858</b>B, infrared image <b>859</b>, initial video <b>960</b>, initial depth images <b>961</b>A-N, and time coordinates. Such communications, for example, may transport packet data via the short range XCVRs <b>1020</b> over the wireless connections <b>925</b> and <b>937</b> to and from the eyewear device <b>100</b> as shown in <figref idref="DRAWINGS">FIG. <b>9</b></figref>. Such communications, for example, may also transport data utilizing IP packet data transport via the WWAN XCVRs <b>1010</b> over the network (e.g., Internet) <b>995</b> shown in <figref idref="DRAWINGS">FIG. <b>9</b></figref>. Both WWAN XCVRs <b>1010</b> and short range XCVRs <b>1020</b> connect through radio frequency (RF) send-and-receive amplifiers (not shown) to an associated antenna (not shown).

0117The mobile device <b>990</b> further includes a microprocessor, shown as CPU <b>1030</b>, sometimes referred to herein as the host controller. A processor is a circuit having elements structured and arranged to perform one or more processing functions, typically various data processing functions. Although discrete logic components could be used, the examples utilize components forming a programmable CPU. A microprocessor for example includes one or more integrated circuit (IC) chips incorporating the electronic elements to perform the functions of the CPU. The processor <b>1030</b>, for example, may be based on any known or available microprocessor architecture, such as a Reduced Instruction Set Computing (RISC) using an ARM architecture, as commonly used today in mobile devices and other portable electronic devices. Other processor circuitry may be used to form the CPU <b>1030</b> or processor hardware in smartphone, laptop computer, and tablet.

0118The microprocessor <b>1030</b> serves as a programmable host controller for the mobile device <b>990</b> by configuring the mobile device <b>990</b> to perform various operations, for example, in accordance with instructions or programming executable by processor <b>1030</b>. For example, such operations may include various general operations of the mobile device, as well as operations related to the camera misalignment compensation programming <b>945</b> and communications with the eyewear device <b>100</b> and server system <b>998</b>. Although a processor may be configured by use of hardwired logic, typical processors in mobile devices are general processing circuits configured by execution of programming.

0119The mobile device <b>990</b> includes a memory or storage device system, for storing data and programming. In the example, the memory system may include a flash memory <b>1040</b>A and a random access memory (RAM) <b>1040</b>B. The RAM <b>1040</b>B serves as short term storage for instructions and data being handled by the processor <b>1030</b>, e.g., as a working data processing memory. The flash memory <b>1040</b>A typically provides longer term storage.

0120Hence, in the example of mobile device <b>990</b>, the flash memory <b>1040</b>A is used to store programming or instructions for execution by the processor <b>1030</b>. Depending on the type of device, the mobile device <b>990</b> stores and runs a mobile operating system through which specific applications, including camera misalignment compensation programming <b>945</b>, are executed. Applications, such as the camera misalignment compensation programming <b>945</b>, may be a native application, a hybrid application, or a web application (e.g., a dynamic web page executed by a web browser) that runs on mobile device <b>990</b>. Examples of mobile operating systems include Google Android, Apple iOS (I-Phone or iPad devices), Windows Mobile, Amazon Fire OS, RIM BlackBerry operating system, or the like.

0121It will be understood that the mobile device <b>990</b> is just one type of host computer in the camera misalignment compensation system <b>900</b> and that other arrangements may be utilized. For example, a server system <b>998</b>, such as that shown in <figref idref="DRAWINGS">FIG. <b>9</b></figref>, may compensated for misalignment in the depicted images after generation of the initial images <b>961</b>A-N.

0122<figref idref="DRAWINGS">FIGS. <b>11</b>A, <b>11</b>B, and <b>11</b>C</figref> are flowcharts <b>1100</b>, <b>1120</b>, and <b>1130</b> illustrating the operation of the eyewear device <b>100</b> and/or other components of the camera misalignment compensation system (e.g., one or more of the processors <b>912</b>, <b>932</b> executing instructions stored in memory <b>934</b>). The steps are described with reference to hardware described herein but are not to be limited to such implementations. Although shown as occurring serially, the blocks of <figref idref="DRAWINGS">FIGS. <b>11</b>A, <b>11</b>B, and <b>11</b>C</figref> may be reordered or parallelized depending on the implementation. Furthermore, one of skill in the art will understand from the description herein that one or more steps/blocks may be omitted, and one or more additional/alternative steps may be incorporated.

0123At block <b>1102</b>, identify a pitch angle offset between sensors/cameras of a stereoscopic camera system. The stereoscopic camera system may include a first camera <b>114</b>A and a second camera <b>114</b>B. In one example, identifying the pitch angle offset includes first determining a first pitch angle of a first camera (block <b>1122</b>; <figref idref="DRAWINGS">FIG. <b>11</b>B</figref>). Then, determining a second pitch angle of a second camera (block <b>1124</b>; <figref idref="DRAWINGS">FIG. <b>11</b>B</figref>). And, then, determining the pitch angle offset from a difference between the first pitch angle and the second pitch angle (block <b>1126</b>; <figref idref="DRAWINGS">FIG. <b>11</b>B</figref>). The pitch angle offset may be stored in memory (e.g., memory <b>934</b>) and retrieve through a call (e.g., from processor <b>932</b>) to determine the pitch angle offset.

0124In another example, identification of pitch angle offset is based on flexure of the frame. One or more flex sensors (e.g., a Wheatstone bridge on a flexible PCB within the frame of the eyewear device <b>100</b>) determine flexure of the frame. The amount of flexure corresponds to a flexure offset. The flexure offset may be the identified pitch angle offset for may be used to adjust pitch angle offset determined in another manner.

0125At block <b>1104</b>, determine misalignment of the first and second cameras from the identified pitch angle offset. The misalignment may be a number of lines or pixels between where an image feature (e.g., image feature <b>802</b><i>b </i>in <figref idref="DRAWINGS">FIG. <b>8</b>F</figref>) would be expected to appear in an image and where it appears in the image (e.g., image feature <b>802</b><i>b </i>in <figref idref="DRAWINGS">FIG. <b>8</b>G</figref>). The misalignment may be calculated based on a known relationship between pitch angle offset and number of pixels. In an example, a pitch angle offset of 3.56 degrees may correspond to a range of 40-75 pixels.

0126At block <b>1106</b>, determine a relative compensation delay responsive to the determined misalignment. In one example, determining the relative compensation delay includes synchronizing readouts of the first and second cameras (block <b>1132</b>; <figref idref="DRAWINGS">FIG. <b>11</b>C</figref>). Then, determining an offset time corresponding to the determined misalignment (block <b>1134</b>; <figref idref="DRAWINGS">FIG. <b>11</b>C</figref>). And, then, setting the relative compensation delay to the determined offset time (block <b>1136</b>; <figref idref="DRAWINGS">FIG. <b>11</b>C</figref>). In another example, determining the relative compensation delay includes determining the relative compensation delay directly from the determined misalignment without first determining an offset time.

0127At block <b>1108</b>, introduce the relative compensation delay. In one example, relative compensation delay is introduced after exposure/capture, e.g., by changing the vertical blanking interval of a camera in order to minimize compensation delay between feature points of first and second image streams from first and second cameras. In another example, the relative compensation delay is introduced prior to exposure/capture, e.g., by configuring the exposure delay such that feature points are exposed at substantially the same time.

0128At block <b>1110</b>, produce a stereoscopic image on the display from first and second image streams with the introduced relative compensation delay to compensate for the pitch angle offset. In one example, image processor <b>912</b> adjusts the image streams for presentation on the image displays <b>180</b>A and <b>180</b>B by the image display driver <b>942</b>.

0129The camera misalignment compensation functionality described herein for the eyewear device <b>100</b>, mobile device <b>990</b>, and server system <b>998</b> can be embodied in one or more applications as described previously. According to some examples, “function,” “functions,” “application,” “applications,” “instruction,” “instructions,” or “programming” are program(s) that execute functions defined in the programs. Various programming languages can be employed to create one or more of the applications, structured in a variety of manners, such as object-oriented programming languages (e.g., Objective-C, Java, or C++) or procedural programming languages (e.g., C or assembly language). In a specific example, a third party application (e.g., an application developed using the ANDROID™ or IOS™ software development kit (SDK) by an entity other than the vendor of the particular platform) may be mobile software running on a mobile operating system such as IOS™, ANDROID™ WINDOWS® Phone, or another mobile operating systems. In this example, the third-party application can invoke API calls provided by the operating system to facilitate functionality described herein.

0130Hence, a machine-readable medium may take many forms of tangible storage medium. Non-volatile storage media include, for example, optical or magnetic disks, such as any of the storage devices in any computer(s) or the like, such as may be used to implement the client device, media gateway, transcoder, etc. shown in the drawings. Volatile storage media include dynamic memory, such as main memory of such a computer platform. Tangible transmission media include coaxial cables; copper wire and fiber optics, including the wires that comprise a bus within a computer system. Carrier-wave transmission media may take the form of electric or electromagnetic signals, or acoustic or light waves such as those generated during radio frequency (RF) and infrared (IR) data communications. Common forms of computer-readable media therefore include for example: a floppy disk, a flexible disk, hard disk, magnetic tape, any other magnetic medium, a CD-ROM, DVD or DVD-ROM, any other optical medium, punch cards paper tape, any other physical storage medium with patterns of holes, a RAM, a PROM and EPROM, a FLASH-EPROM, any other memory chip or cartridge, a carrier wave transporting data or instructions, cables or links transporting such a carrier wave, or any other medium from which a computer may read programming code and/or data. Many of these forms of computer readable media may be involved in carrying one or more sequences of one or more instructions to a processor for execution.

0131The scope of protection is limited solely by the claims that now follow. That scope is intended and should be interpreted to be as broad as is consistent with the ordinary meaning of the language that is used in the claims when interpreted in light of this specification and the prosecution history that follows and to encompass all structural and functional equivalents. Notwithstanding, none of the claims are intended to embrace subject matter that fails to satisfy the requirement of Sections 101, 102, or 103 of the Patent Act, nor should they be interpreted in such a way. Any unintended embracement of such subject matter is hereby disclaimed.

0132Except as stated immediately above, nothing that has been stated or illustrated is intended or should be interpreted to cause a dedication of any component, step, feature, object, benefit, advantage, or equivalent to the public, regardless of whether it is or is not recited in the claims.

0133It will be understood that the terms and expressions used herein have the ordinary meaning as is accorded to such terms and expressions with respect to their corresponding respective areas of inquiry and study except where specific meanings have otherwise been set forth herein. Relational terms such as first and second and the like may be used solely to distinguish one entity or action from another without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms “comprises,” “comprising,” “includes,” “including,” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises or includes a list of elements or steps does not include only those elements or steps but may include other elements or steps not expressly listed or inherent to such process, method, article, or apparatus. An element preceded by “a” or “an” does not, without further constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

0134Unless otherwise stated, any and all measurements, values, ratings, positions, magnitudes, sizes, and other specifications that are set forth in this specification, including in the claims that follow, are approximate, not exact. Such amounts are intended to have a reasonable range that is consistent with the functions to which they relate and with what is customary in the art to which they pertain. For example, unless expressly stated otherwise, a parameter value or the like may vary by as much as ±10% from the stated amount.

0135In addition, in the foregoing Detailed Description, various features are grouped together in various examples for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed examples require more features than are expressly recited in each claim. Rather, as the following claims reflect, the subject matter to be protected lies in less than all features of any single disclosed example. Thus, the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separately claimed subject matter.

0136While the foregoing has described what are considered to be the best mode and other examples, it is understood that various modifications may be made therein and that the subject matter disclosed herein may be implemented in various forms and examples, and that they may be applied in numerous applications, only some of which have been described herein. It is intended by the following claims to claim any and all modifications and variations that fall within the true scope of the present concepts.